The present invention relates generally to data storage cartridges and drive units for reading data from and writing data to such cartridges.
Data storage cartridges are commonly used for such tasks as safeguarding valuable information stored on computer systems. In performing such a task, a drive unit located either internally or externally to the computer system is used to copy data from the computer system onto a data cartridge. The data storage cartridge may then be stored in a safe location. Should the information on the computer system later become damaged, the data storage cartridge could then be used to retrieve the lost or damaged data.
In addition to the data back-up function described above, data storage cartridges are also often used as primary data storage capacity. Functioning in this manner, data storage cartridges serve as a means for storing computer or other equipment information for later retrieval.
Various types of data storage media are used in data storage cartridges. One common type of media is magnetic tape. In a magnetic tape data storage cartridge, the tape is wound around spools within the cartridge to allow movement of the tape past the read-write head of a cartridge drive unit.
The drive unit, in addition to the read-write head, generally contains a motor for moving the tape or other media, electronics for controlling the drive, and a mechanism for orienting the cartridge within the drive and for securely holding it in place. It is important to proper operation of the drive unit that the data storage cartridge be closely aligned with the drive read/write head while in operation.
One present configuration for achieving this alignment employs a three point contact system between the drive unit and the data storage cartridge. In this configuration, all three points are located on an upwardly facing surface of the cartridge, limiting its upward movement with respect to the drive. Since three points define a plane, this arrangement allows the data storage cartridge to be located fairly precisely with respect to the drive read-write head. It has been found, however, that this three point contact system sometimes causes instability in alignment, particularly when the drive is exposed to vibration or other physical shock while reading from or writing to a data storage cartridge.
As information storage needs have grown, so have the demands placed upon data storage cartridges. In an effort to address these demands, cartridge manufacturers strive for ways to increase the storage capacity of data storage cartridges. Complicating this task, however, is the limitation imposed by the physical size envelope available for cartridges.
Many cartridge drive units are mounted in computers or other electronic devices. This arrangement limits the physical space available for cartridges and the drives that must receive them and thus limits the ultimate physical size attainable for cartridges. When designing new, larger capacity cartridges, manufacturers must, thus, take advantage of existing space.
One such new, larger cartridge has been designed to enable the holding of more media. Unfortunately, the nature of this new design has forced the elimination of one of the previously used contact surfaces in the three point planar contact system.